@SuwOost Great, glad you got your BlueROV1 complete!
The BlueROV1 was retired a couple years ago so we haven’t worked on that for quite some time.
We have ballast trimming notes in our BlueROV2 Assembly Guide. As the other forum members mentioned in your forum thread, the float level doesn’t matter as much and users definitely have different preferences.
Traditionally, we trim to be as close to neutrally buoyant as possible with the vehicle being slightly positively buoyant so the ROV will come back to the surface on its own in case of a loss of power. You can have it more buoyant, but it will just take more power to stay at depth, decreasing your dive time.
Whether nor not you want the ROV to float is down to personal preference. Some pilots prefer a negatively buoyant vehicle, others completely neutral, and others a slightly positively buoyant one. How the vehicle sits at the surface if positively buoyant is not as important at the attitude when fully submerged.
…a Positive ROV will surface if you cut Tether… a nagative ROV is professionally Only used for special tasks where its required or an advantage… but i alllways prefer it a little positive bec you dont have to use so much downtrust to go up from seabed…and dont ruin the visibillity …but here we have batterypower, and want to save battery if you are just staying for filming, then i would have it a bit negative bec you dont use power sitting on seabed